Control is applied to components in motor vehicles such as, for example, actuators or injectors on the engine using control devices. It is necessary for this purpose for the control device to receive and transmit information or data. It is known to exchange data between sensors/actuators and an associated control device by way of digital interfaces. For reliable communication in motor vehicles, PSI5 interfaces, for example, are used as digital interfaces.
PSI5 (Peripheral Sensor Interface 5) refers to a digital interface for sensors that is based on a two-wire lead and is used in automotive electronics to connect peripheral sensors to electronic control devices. Point-to-point and bus configurations are supported, with asynchronous and synchronous communication.
PSI5 operates on the principle of current interface modulation of a transmitting current for data transfer on the power supply lead. A high level of interference resistance is achieved thanks to the relatively high signal current and the use of Manchester bit coding, with the result that it is sufficient to use an economical two-wire lead for wiring.
It is possible to awaken and deactivate sensors in targeted fashion using upstream data, in which context the power consumption of the PSI5 bus system can be reduced.
Sensors having a PSI5 interface, and correspondingly also receivers and transceivers for receiving sensor data, have been used for several years in the automotive sector. Bidirectional communication is also possible via the synchronization pulses, the data occurring from the control device to the sensor via the presence or absence of synchronization pulses.
All receivers and transceivers possess a Manchester decoder and an SPI interface for data transfer to the microcontroller. In order to generate synchronization pulses, receivers and transceivers that are on the market require a higher voltage (Vsync) than the sensor supply voltage for the sensor quiescent current (VAS). There is also no time stamp, and thus no indication as to how old the received data are.
It is noteworthy that engine control devices used at present do not offer an overall solution, or an economical overall solution, for the acquisition of Manchester-coded data or for bidirectional communication with PSI5 sensors. There is therefore also no possibility of detecting engine tuning.